As a method of achieving augmented reality with the use of an image recognition technology, a method of using a marker is known. However, an inorganic marker undermines the design. In that regard, a technology is known in which no marker is used and an object is identified using a local feature value.
During image recognition used particularly for achieving augmented reality (for detection of objects from images), it is often the case that images captured in various realty environments are used. For that reason, there is a demand for an image recognition technology that is robust even against the changes in the environment.